When installing Schema Registry, SAM, Druid, and Superset, you require a relational data
store to store metadata. You can use either MySQL, Postgres, Oracle, or MariaDB. These topics
describe how to install MySQL, Postgres, and Oracle and how create a databases for SAM and
Schema Registry. If you are installing on an existing HDP cluster by using Superset, you can
skip the installation instructions, because MySQL was installed with Druid. In this case,
configure the databases.

Note

You should install either Postgres, Oracle or MySQL; both are not necessary. It is
recommended that you use MySQL.

Warning

If you are installing Postgres, you must install Postgres 9.5 or later for SAM and Schema
Registry. Ambari does not install Postgres 9.5, so you must perform a manual Postgres
installation.